batch purity comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Last reviewed on 2026-07-27. Where a claim depends on a specific study, the study is described rather than over-claimed.
Regulatory treatment varies by jurisdiction. In Russia the compound is a registered prescription product, while in the European Union and the United States it is generally handled as a research chemical without a marketing authorization. Suppliers therefore operate outside pharmaceutical oversight, and buyers rely on supplier documentation for purity and identity claims. Chain of custody and third-party testing are the main verification tools. Analysts note that the absence of a pharmacopoeial monograph for research-grade material limits standardization across vendors.
Purity assessment relies mainly on reverse-phase high-performance liquid chromatography with ultraviolet detection. Because the peptide lacks a strong chromophore, detection often uses backbone absorbance near 214 nm. Identity is confirmed by mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, comparing the measured mass against the expected value. Amino acid analysis can verify composition after acid hydrolysis. Diastereomer content and residual counterions are reported less often, although both can influence biological assays.
Naming for this compound is not fully standardised in English sources. The spelling Selanc appears in some transliterations, and catalogue entries may instead list the peptide sequence itself as the identifier. Reference material sometimes groups it with other short synthetic peptides studied for behavioural effects, which can create confusion when citations are compared. Distinguishing the exact sequence from related tuftsin analogues is therefore a practical first step when reviewing any dataset or specification sheet.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, frequently abbreviated as TKPRPGP. It was designed as a structural analogue of tuftsin, a naturally occurring tetrapeptide released by enzymatic cleavage of the immunoglobulin heavy chain. The two additional proline residues at the C-terminal end extend the parent chain and change how the molecule behaves in solution. The free peptide has a calculated molecular mass of approximately 751.9 g/mol and is generally supplied as a lyophilised white to off-white powder.
Development work on the compound began in the 1980s and 1990s at the Institute of Molecular Genetics in Moscow, within the same research programme that produced the peptide Semax. Early investigators sought a tuftsin derivative with improved resistance to enzymatic breakdown and with activity in the central nervous system after peripheral administration. Most of the primary literature from this period was published in Russian, a factor that still shapes how easily the findings can be checked by outside groups.
| Property | Value | Notes |
|---|---|---|
| Typical purity report | 95% or higher by HPLC | Area percentage at 214 nm |
| Identity confirmation | Mass spectrometry | Electrospray or MALDI |
| Powder storage | -20 C, desiccated | Protect from light |
| Solution storage | 2-8 C short term | Freeze aliquots for longer |
| Quality document | Certificate of analysis | States method and value |
Reverse-phase high-performance liquid chromatography with ultraviolet detection near 214 nanometres is the standard purity method. Mass spectrometry, typically electrospray ionisation, confirms identity through the expected mass-to-charge pattern. Amino acid analysis can verify composition independently. Chiral purity requires separate techniques such as derivatisation followed by chromatographic separation, and such data are rarely reported for research-grade material.
Quantification in biological matrices relies on liquid chromatography coupled to tandem mass spectrometry with stable-isotope internal standards. Low plasma concentrations and adsorption to container surfaces both complicate measurement. Solid-phase extraction is often needed to reduce matrix interference before injection. Reported limits of quantification differ widely between laboratories, which makes direct comparison of pharmacokinetic results difficult and limits meta-analysis.
Peptide bonds are vulnerable to protease attack, and Selank is no exception. Measured half-life in serum is short, on the order of minutes in several reports, which explains why intranasal administration is the common route described in the literature. Absorption across the nasal mucosa partially bypasses first-pass hepatic metabolism. Quantitative data on human bioavailability remain limited and are difficult to compare across studies.
Pharmacokinetic data are sparse and largely derived from animal work. After intranasal administration the peptide appears in plasma within minutes, and reported half-lives are short, on the order of minutes to tens of minutes. Degradation proceeds through ordinary proteolytic cleavage into constituent amino acids and smaller fragments. Direct evidence that intact Selank reaches brain tissue in meaningful amounts is limited, and the extent of blood-brain barrier penetration is debated. Some authors argue that fragments, not the parent peptide, carry much of the observed activity.
Published clinical work is concentrated in Russian-language journals and generally involves small samples without independent replication. Systematic reviews in English note the shortage of randomised, placebo-controlled trials and the difficulty of verifying methods from translated reports. Outcome measures vary between studies, which complicates pooling of results. Interest in the compound as a cognitive or anxiolytic agent therefore rests on a thinner evidence base than the volume of citations suggests. Replication in well-powered trials with preregistered endpoints would be needed before firm conclusions about efficacy can be drawn.
Proposed mechanisms centre on the GABAergic system. Animal and tissue studies report changes in GABA-A receptor expression and reduced activity of GABA transaminase, the enzyme that degrades GABA. Effects on monoamine turnover, including serotonin and dopamine pathways, are also described, and a separate line of work links the peptide to increased expression of brain-derived neurotrophic factor in hippocampal tissue. Most of these findings come from rodent models and cell preparations. How the individual observations combine into a single coherent mode of action is not settled.
Characterization of Selank in laboratory settings relies on standard peptide analytical techniques. Reverse-phase high-performance liquid chromatography separates the peptide from related impurities and degradation products, while mass spectrometry confirms molecular identity through accurate mass measurement. Amino acid analysis and peptide sequencing verify the primary structure when reference material is unavailable. Because Selank is a short chain, fragmentation-based analysis produces a diagnostic ion pattern that supports confident identification.
Peptide stability depends strongly on temperature, moisture, and pH. Lyophilized Selank is generally most stable when stored cold and dry, with freezer temperatures commonly used for long-term storage. In solution, the compound is susceptible to hydrolysis and to microbial growth if it is not handled aseptically. The C-terminal proline-rich extension appears to slow enzymatic cleavage relative to tuftsin, though quantitative degradation rates vary with the matrix and the conditions tested. Published stability data specific to Selank remain sparse.
== Career == Davies’ research focuses on the causes, prevention, and self-management of type 2 diabetes, including early onset type 2 diabetes. She has contributed to clinical trials and international consensus guidelines on diabetes care.
=== Medical and health sciences === Medical use of HPLC typically use mass spectrometer (MS) as the detector, so the technique is called LC-MS or LC-MS/MS for tandem MS, where two types of MS are operated sequentially. When the HPLC instrument is connected to more than one detector, it is called a hyphenated LC system. Pharmaceutical applications are the major users of HPLC, LC-MS and LC-MS/MS. This includes drug development and pharmacology, which is the scientific study of the effects of drugs and chemicals on living organisms, personalized medicine, public health and diagnostics. While urine is the most common medium for analyzing drug concentrations, blood serum is the sample collected for most medical analyses with HPLC. One of the most important roles of LC-MS and LC-MS/MS in the clinical lab is the Newborn Screening (NBS) for metabolic disorders and follow-up diagnostics. The infants' samples come in the shape of dried blood spot (DBS), which is simple to prepare and transport, enabling safe and accessible diagnostics, both locally and globally. Other methods of detection of molecules that are useful for clinical studies have been tested against HPLC, namely immunoassays. In one example of this, competitive protein binding assays (CPBA) and HPLC were compared for sensitivity in detection of vitamin D. Useful for diagnosing vitamin D deficiencies in children, it was found that sensitivity and specificity of this CPBA reached only 40% and 60%, respectively, of the capacity of HPLC. While an expensive tool, the accuracy of HPLC is nearly unparalleled.
=== Personal life === Flory was born in Sterling, Illinois, on June 19, 1910 to Ezra Flory and Martha Brumbaugh. His father worked as a clergyman-educator, and his mother was a school teacher. His ancestors were German Huguenots, who traced their roots back to Alsace. He first gained an interest in science from Carl W Holl, who was a chemistry professor at Manchester College. In 1936, he married Emily Catherine Tabor. They had three children together: Susan Springer, Melinda Groom and Paul John Flory, Jr. His first position was at DuPont with Wallace Carothers. He was posthumously inducted into the Alpha Chi Sigma Hall of Fame in 2002. Flory died on September 9, 1985, following a heart attack. His wife Emily died in 2006 aged 94.
(R)-3,4-Methylenedioxy-N-methylamphetamine ([R]-MDMA), also known as (R)-midomafetamine or as levo-MDMA, is the (R)- or levorotatory (l-) enantiomer of 3,4-methylenedioxy-N-methylamphetamine (MDMA; midomafetamine; "ecstasy"), a racemic mixture of (R)-MDMA and (S)-MDMA. Like MDMA, (R)-MDMA is an entactogen or empathogen. It is taken by mouth. The drug is a serotonin–norepinephrine releasing agent (SNRA) and weak serotonin 5-HT2A receptor agonist. It has substantially less or no significant dopamine-releasing activity compared to MDMA and (S)-MDMA. In preclinial studies, (R)-MDMA shows equivalent therapeutic-like effects to MDMA, such as increased prosocial behavior, but shows reduced psychostimulant-like effects, addictive potential, and serotonergic neurotoxicity. In clinical studies, (R)-MDMA produces similar effects to MDMA and (S)-MDMA, but is less potent and has a longer duration. (R)-MDMA was first described in enantiopure form by 1978. Under the developmental code names EMP-01, developed by AtaiBeckley, and DT402 (formerly MM402), developed by Definium Therapeutics (formerly MindMed), it is under development for the treatment of post-traumatic stress disorder (PTSD), social phobia, and pervasive development disorders (PDDs) such as autism. It is thought that (R)-MDMA might have a better safety profile than MDMA itself whilst retaining its therapeutic benefits.
According to state law, if a physician's participation in the execution is prohibited for reasons of medical ethics, then the death ruling can be made by the state medical examiner's office. After confirmation that death has occurred, a coroner signs the condemned's death certificate.
Sources: en.wikipedia.org
=== Hematopoietic stem cell transplantation === Hematopoietic stem cell transplantation (HSCT) is a potentially curative treatment for both alpha and beta thalassemia. It involves replacing the dysfunctional stem cells in the bone marrow with healthy cells from a well-matched donor. Cells are ideally sourced from human leukocyte antigen matched relatives; the procedure is more likely to succeed in children rather than adults. The first HSC transplant for thalassemia was carried out in 1981 on a patient with beta thalassemia major. Since then, a number of patients have received bone marrow transplants from healthy matched donors, although this procedure has a high level of risk. In 2018 an unborn child with hydrops fetalis, a potentially fatal complication of alpha thalassemia, was successfully transfused in utero with her mother's stem cells. HSCT is a dangerous procedure with many possible complications; it is reserved for patients with life-threatening diseases. Risks associated with HSCT can include graft-versus host disease, failure of the graft, and other toxicity related to the transplant. In one study of 31 people, the procedure was successful for 22 whose hemoglobin levels improved to the normal range, in seven the graft failed and they continued to live with thalassemia, and two died of transplantation-related causes.
Wenger led training sessions, but delegated responsibility to his coaching staff, who predominantly work with the players. He split the squad into groups, observing and supervising the drills. A typical training session under Wenger lasted 90 minutes, which was timed and staged precisely, and included co-ordination techniques, positional play and small-sided games. Wenger spent the day before a match focusing on the mental and tactical approach of his squad and varied his training style. Wenger regarded a well-balanced diet as an essential part of a player's preparation. He was influenced by his time in Japan, where "the whole way of life there is linked to health. Their diet is basically boiled vegetables, fish and rice. No fat, no sugar. You notice when you live there that there are no fat people". At Arsenal, Wenger brought in dieticians to explain the benefits of a healthy lifestyle, and acquired the help of Philippe Boixel, an osteopath for the France national team, to realign the players' bodies each month. Plyometrics, exercises designed to strengthen the muscles, were introduced and Wenger routinely made players stretch before and after matches. Until 2004, he encouraged his players to take Creatine for increased stamina, later stopping when he noticed side-effects. The innovations had a desirable effect on the team as it prolonged the careers of his defence, and made Arsenal stronger in the second half of seasons. Though Wenger's methods were common in Italian football, they had been unsuccessfully trialled in England until his arrival.
=== Grasslands === It was reported that approximately 34 percent (33.85 million mu; 22,600 km2) of the region's total surface consisted of grassland. This figure is down from approximately 40 percent in the 1990s. The grasslands are spread over the dry desert-steppe area in the northeast (which forms a part of the Inner Mongolian steppe region), and the hilly pastures located on the semi-arid Loess Plateau in the south. It is ascertained that the grasslands of Ningxia have been degraded to various degrees. Scientists debate the extent to which this degradation occurs over space and time. Historical research has also found limited evidence of expanding grassland degradation and desertification in Ningxia. A major component of land management in Ningxia is a ban on open grazing, which has been in place since 2003. The ecological and socio-economic effects of this Grazing Ban in relation to the grasslands and pastoralists' livelihood are contested. The ban stipulates that animal husbandry be limited to enclosed pens and no open grazing be permitted in certain time periods set by the Autonomous Region's People's Government.
== Awards and honors == 1993 – Outstanding Investigator Grant, National Cancer Institute 2003 – Research Award, American Cancer Society Scientific 2010 – Astellas USA Foundation Award, American Society for Pharmacology and Experimental Therapeutics
==== Norepinephrine ==== Similar to dopamine, amphetamine dose-dependently increases the level of synaptic norepinephrine, the direct precursor of epinephrine. Amphetamine is believed to affect norepinephrine analogously to dopamine. In other words, amphetamine induces competitive NET reuptake inhibition, TAAR1-mediated non-competitive reuptake inhibition and reverse transport at phosphorylated NET, CAMKIIα-mediated NET efflux independent of TAAR1, and norepinephrine release from VMAT2. In locus coeruleus norepinephrine neurons, TAAR1-dependent RhoA signaling promotes EAAT3 internalization and subsequent glutamate reuptake inhibition.
Sources: en.wikipedia.org
=== α+β === α+β proteins are a class of structural domains in which the secondary structure is composed of α-helices and β-strands that occur separately along the backbone. The β-strands are therefore mostly antiparallel. Common examples include the ferredoxin fold, ribonuclease A, and the SH2 domain.
Theriac or theriaca is a medical concoction originally labelled by the Greeks in the 1st century AD and widely adopted in the ancient world as far away as Persia, China and India via the trading links of the Silk Route. It was an alexipharmic, or antidote for a variety of poisons and diseases. It was also considered a panacea, a term for which it could be used interchangeably: in the 16th century Adam Lonicer wrote that garlic was the rustic's theriac or Heal-All. The word theriac comes from the Greek term θηριακή (thēriakē), a feminine adjective signifying "pertaining to animals", from θηρίον (thērion), "wild animal, beast". The ancient bestiaries included information—often fanciful—about dangerous beasts and their bites. When cane sugar was an exotic Eastern commodity, the English recommended the sugar-based treacle as an antidote against poison, originally applied as a salve. By extension, treacle could be applied to any healing property: in the Middle Ages the treacle (i.e. healing) well at Binsey was a place of pilgrimage. Norman Cantor observes that the remedy's supposed effect followed the homeopathic principle of "the hair of the dog", whereby a concoction containing some of the poisonous (it was thought) flesh of the serpent would be a sovereign remedy against the creature's venom: in The Book of Holy Medicines, Henry of Grosmont, 1st Duke of Lancaster, wrote that "the treacle is made of poison so that it can destroy other poisons".
BAFF-R (BAFF receptor) BCMA (B cell maturation antigen) TACI (transmembrane activator and calcium modulator and cyclophylin ligand interactor) When BAFF binds to BAFF-R and BCMA on B cells, levels of Bcl-2, a survival factor, are increased. When all three BAFF receptors are stimulated, levels of NF kappa B, which contributes to cell proliferation and differentiation, are increased in the nucleus. Another B-cell activator similar to BAFF is APRIL (A proliferation-inducing ligand), but APRIL activates only BCMA and TACI, not BAFF-R. Belimumab reduces the number of circulating B cells, but anti-CD20 monoclonal antibodies reduce the number even more. It is possible that belimumab binds primarily to circulating soluble BAFF and therefore does not induce the antibody-dependent cellular cytotoxicity that could be expected from this IgG1-type antibody..
In 1973 "by Direction of the President, Major General Liu Wan-Tsai, Chinese Air Force, [was] awarded the Legion of Merit (Degree of Officer) for exceptionally meritorious service as Air Attache, Embassy of the Republic of China, Washington, D.C., from 4 April 1969 to 27 July 1972." In 1996, Lieutenant General Roméo Dallaire of the Canadian Army was made an Officer of the Legion for his role as Commander of the United Nations peacekeeping force in Rwanda during the civil war and subsequent genocide. On 18 December 1980 Major General Shlomo Inbar, Israel Army, was made an Officer of the Legion of Merit for his exceptionally meritorious conduct in the outstanding performance of duties as Defense and Armed Forces Attache, Embassy of Israel to the United States of America, from July 1977 to August 1980. In 2000, Lieutenant General Danfer G. Suarez was made an Officer of the Legion "Exceptionally meritorious conduct in the performance of outstanding services as the Peruvian Air Attache from 1997 to 1998. In 2006, Lieutenant General Nick Houghton, British Army, "in recognition of gallant and distinguished services during coalition operations in Iraq." In 2007, Lieutenant General Sir Robert Fry, Royal Marines, "in recognition of gallant and distinguished service during coalition operations in Iraq. Lieutenant General Tariq Khan became the fourth Pakistani officer to receive the award for meritorious services as a liaison officer at CENTCOM during Operations Enduring Freedom (December 9, 2007).
Sources: en.wikipedia.org
Purity is usually reported as an HPLC area percentage, most often measured at 214 nm. Identity is confirmed separately by mass spectrometry. A certificate of analysis should state both the method and the observed value.
Dry powder is kept frozen, desiccated, and shielded from light. Dissolved material is aliquoted and frozen to limit freeze-thaw cycles. Short-term refrigerated storage is common for working solutions.
Russia registers it as a prescription nasal product. Most other markets classify it as a research chemical with no approved medical use. Oversight of purity and labeling is consequently minimal in those markets.
The sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, commonly written as TKPRPGP. It shares the first four residues with tuftsin and carries three prolines in the chain. The proline-rich tail is the main structural feature that separates it from the parent tetrapeptide.